Angle flow measurement devices, such as aircraft angle of attack and angle of sideslip measurement devices, are subject to degradation and damage resulting from a variety of sources, such as foreign object damage (“FOD”), internal electrical arcing provided by a lighting strike, environmental moisture effects, or incursion of foreign matter. These events, if undetected, can affect both the static and dynamic angular measurement accuracy of these devices. Traditionally, these errors must be detected by manual inspection of the sensor or by comparison of the sensor to other sensors installed on the platform. In some platform applications, a major limitation of the existing method is that manual inspections can only be performed when the platform is on the ground, or otherwise not in use, and is performed only after a concern is identified by some other means. A sensor cross-comparison method, which might be used in operation, is usually able to detect only gross inaccuracies and may be susceptible to common mode issues. The present invention addresses these limitations by providing a means to detect degradation and damage within the device, while in use and on a regular basis, without the reliance on external monitoring.